Connecting the iron girdebs of bbidcres



par n sTATEs PATENT oFF-TOE.

JOEL T. HAM, or COVINGTON, KENTUOKY.

CONNECTING THE IRON GIRDERS OF BRIDGES.

Speccaton of Letters Patent No. 24,460, dated June 21, 18559.

To all whom 'it may concern:

Be it known that I, JOEL T. HAM, of Covington, in the county of Kenton and State of Kentucky, have invented certain new and useful Improvements in Wrought- Iron Girders for Bridges and other Structures; and I do hereby declare that the following is a full, clear, and exact description of the same, reference being had to the accompanying drawings, forming part of this specification, in which- Figure 1 is a side elevation of a bridge constructed according to my invention. Fig. 2 is a side view on a larger scale, representing the manner of connecting the feet of the posts and braces to a short section of chord. Fig. 2* is a transverse section corresponding with Fig. 2. Fig. 2** exhibits the transverse sectional form of the iron used in the bridge. Figs. 3, t, and 5, are transverse sectional views illustrating different forms of iron that may be used in carrying outmy invention, and their application. Figs. 6 and 7 are views of similar character' to Figs. 2 and 2*, exhibiting the manner of connecting the heads of the posts and braces with the top chord. Figs. 8 and 9 are views of similar character to Figs. 2 and 2:, exhibiting the application of indiarubber springs at the connections of the feet of the posts and braces with the chords.

Similar letters of reference indicate corresponding parts wherever they occur in the several figures.

A, A, are the bottom and top chords made of wrought iron, the transverse section of which forms three sides of a hollow square, the concavity in both chords being arranged at the bottom.

E, E, (Figs. 2, 2*, 8 and 9), are pieces of iron of similar shape to the chords but suf' ficiently wider to fit over the bottom chord to constitute saddles for the upright posts C, C, and diagonal braces D, D, to rest upon. Saddles E', E, of similar character are placed within the upper chord as shown in Figs. 6 and 7, to receive the upper ends of the posts and braces.

The braces D, D, and posts C, C,vare cut l away at the bottom to form cheeks to lap over and iit to the sides of the saddles E, E,

as shown at a, c, in Figs. 2, 2:, 8 and 9; and to provide vfor the proper iitting of these cheeks, it is desirable that the iron of which the braces are made shall be rather wider than. that of which thesaddles are made, and that of which the posts are made shall be rather wider than that of which the braces are made. Cheeks Z, o, (Figs. 6 and 7,) are formed at the heads of the posts and braces to ft the saddles E, Ef, and. thetop chord A,'is made. of wider iron than the lower ones toviit over the cheeks b, b, of the posts and braces.

F, F, are wrought iron stirrups passing under the lower chord A, and some distance up the sides of the posts C, C, and riveted or bolted to the posts above the chord and braces.

F, F, are strap irons like the stirrups F, F, but reversed in position passing over the top chord A', and some distance down the posts C, C, and riveted or bolted to the posts below the top chord and braces. This method of connecting the posts and braces with thechords provides for the expansion and contraction of all the said parts by changes of temperature, as the saddles are left free to slide to some extent.

C, C, are shoulder pieces secured to the exterior of the lower chord; and o', c', shoulder pieces secured to the interior of the top chord to prevent the saddles moving farther than is necessary to compensate for expansion.

Figs. S and 9 illustrate the employment of india-rubber between the stirrups F, and the lower chord A, for relieving the bridge of the jar of trains passing over it, and thereby preventing the crystallization of the iron. L, is a block of india-rubber placed between two blocks M, N, of cast iron or other hard material; the said blocks having cavities in which the india-rubber is partly received and by which it is kept in place. The upper block M, is kept in place laterally by being received in the concavity of the lower chord A, and it is confined longitudinally within the lower block N, by upward proj ections d, cl, on the latter, which projections also enter the concavity of the lower chord and cause the block N, to be confined later-v ally. When these blocks are employed, the stirrups F, F, are made long enough to han some distance below the chord A, that they may receive the lower blocks N, N, within them; and the latter blocks are provided with downward projections e, e, at each end, to confine them longitudinally within the stirrups. The bridge floor is supposed in the above case to be supported on the bottom chords. When the floor is to be supported on theV top chord, india rubber must be applied between the upper saddle and the said chord to produce a similar effect. In the latter case the top chord must be straight nstead of arched asA represented. The top chord represented is of arched form, and rests upon the abutments. u

B, B, are arches formed of metal Whose section may be of any of therforins represented in Figs. 3, 4,`and 5, riveted or bolted to the posts and braces and also to the bottoni chordat the several points of intersection, and serving to strengthen the truss.

The iron of which the chords,posts, braces, and arches are composed may be rolled to the desired form in bars or plates of as greatY length as convenient, or made of plate iron by swagng; andthe several lengths necessary to form a chord, arch, post or brace may be united by rivets or in any other suitable manner.

What I claim as my invention, and desire to secure by Letters-Patent, is

1. Combining the posts and braces With J. T. HAM.

Witnesses Y H. V. WEAKLEY, L. M. DAYTON. 

